Officials said there were no reports of injuries, but the building was heavily damaged.

About 65 firefighters fought heavy flames and billowing smoke inside of the building. The blaze was soon upgraded to a 2-alarm fire as firefighters battled to gain control of the flames. Fire could be seen climbing through the church roof.

HFD spokesman Capt. Ruy Lozano said two strong firewalls helped contain the fire to the attic, where it started.

The building was empty and the fire was reported by a passerby on the street, witnesses said.

Fire officials said there is no reason yet to suspect arson, but an elder of the congregation said odd circumstances unfolded just before the fire.

Terry Myers said a suspicious-looking person was seen in the building's breezeway. Then the church's security alarm system sounded at 12:10 p.m. and the fire happened shortly after that, he said.

Alice Grabel, a volunteer secretary at the church, said she was the last person in the building when she left at around noon. As she exited, she saw an unfamiliar, heavy-set man wearing a red, black and white striped pullover.

Grabel said the security alarm sounded in an area of the church where karate classes are also held. The room is directly next to where the fire started, she said.

Arson investigators are at the scene trying to determine what caused the fire.

Joe Lamb, a member for 72 years, said the church was organized in 1903. He described the structure as a wood frame and brick facade and said the wood frame of the part that burned was built in 1910.

The blaze comes a day after a 5-alarm fire destroyed an apartment complex under construction just west of downtown. That fire broke out about 12:30 p.m. Tuesday. High winds whipped the flames into an inferno.

None of the firefighters who fought the construction blaze was involved in the church fire since a shift change Tuesday morning brought a different crew on duty for a 24-hour stint, Lozano said.